Enjoyed the first book, rating brought down by several elements that didn't belong. Those are gone here, but this murder mystery isn't as good. Both books were released together (adding a short story between) in one volume later on. Unlike the other two, this novel would not stand on its own.

The tale kicks off with little introduction, nearly in media res. I fumbled to figure out whether Will was Wili (no) and Della was Della (yes), and where they fit in this timeline. Turns out they are now a LONG ways past the time of the first novel, and that past is eventually explored. Will is a cop, a police detective, and was a pretty good one. After he disappeared, his son wrote stories about him, making him out to be Sherlock Holmes. This element would have been great to introduce earlier.

If you haven't figured out from the previous paragraph, time plays a major role in this novel, and time travel is only one way - downstream. This is an interesting aspect, and the author uses this to discuss the end of humanity - were we taken out by an enemy or did we "move on" due to the singularity? The author's views seem clear by the end of the book. He also published an essay a few years later titled "The Coming Technological Singularity".

This book, the first book, the series - all good, but not great. The author is more well known for his trilogy starting with "A Fire Upon the Deep" and his short stories. I rated his collection "True Names and other Dangers" five stars, and would recommend anyone start there.